Many electronic devices, including various portable electronic devices such as so-called smartphones and tablet/pad-styled computers, use a display as a primary mechanism by which a user enters input (such as, but not limited to, alphanumeric information, selections, instructions, and so forth). These displays often utilize any of a variety of techniques to sense a particular present location (and/or movement) of the user's finger or stylus with respect to the display (with the so-called touchscreen display serving as a good example in these regards).
Such a display will sometimes employ active technology to detect a user's finger-based input. This might comprise, for example, transmitting light beams from a large plurality of light transmitters and detecting when particular light beams are broken by the user's finger. In a somewhat analogous manner a display may use an active technology to detect the interactions of the display with a user-borne stylus. In many cases the stylus comprises an active stylus that actively emits one or more signals that the display can receive and utilize, at least in part, to detect a present location of at least a part of the stylus (such as the tip of the stylus) with respect to the display.
Unfortunately, neither a finger-based approach nor a stylus-based approach comprises an objectively best approach for all users, displays, and application settings. In some cases, in fact, it can be desirable for a given device to support both a finger-based approach as well as a stylus-based approach. Accordingly, there are display-based devices that utilize two or more detection methodologies to thereby accommodate both a finger-based and a stylus-based modality of user interaction.
As noted above, however, these various detection technologies are typically “active” and hence consume power. Controlling power consumption has been, and remains, a significant design concern for manufacturers of portable electronic devices. To meet this concern, it is known in the art to require the user to switch between detection modalities to accommodate their present use of a finger or stylus. Unfortunately, such an approach can be distracting and even non-intuitive and confusing to some users.
As another approach, it is known in the art to automatically interleave the use of finger-detection resources with the use of active-stylus-detection resources from one scan period to another. Using this approach avoids applying power to all available detection resources all the time. Unfortunately, this approach can result in considerable latency between the time a user makes a particular action with their finger/stylus and the time when the device reacts in a visually appropriate and corresponding manner.